Dog cloning-no longer science fiction

Since the generation of world's first cloned dog, Snuppy, in 2005, somatic cell nuclear transfer (SCNT) in dogs has been widely applied for producing several kinds of dogs with specific objectives. Previous studies have demonstrated that cloned dogs show normal characteristics in growth, blood parameters and behavioural aspect. Also, canine SCNT technique has been applied to propagate working dogs with excellent abilities in fields such as assistance of disabled people, drugs detection and rescue activity. Because dogs have similar habituation properties and share many characteristics including anatomic and physiological aspects with humans, they are also primary candidates for human disease models. Recently, transgenic dogs that express red fluorescent protein gene constitutively and green fluorescent protein gene conditionally have been generated. In addition, transgenic dogs with an overexpression of peroxisome proliferator-activated receptor-alpha in specific muscles were generated to enhance physical performance. In 2017, Snuppy was recloned with markedly increased pregnancy and delivery rates compared to the statistics from when Snuppy was first cloned. Such striking improvements in the cloning of dogs using SCNT procedures suggest that dog cloning could be applied in many fields of biomedical science for human diseases research, and the application of cloning is no longer science fiction.

Reproductive ability of a cloned male detector dog and behavioral traits of its offspring

In 2007, seven detector dogs were produced by somatic cell nuclear transfer using one nuclear donor dog, then trained and certified as excellent detector dogs, similar to their donor. In 2011, we crossed a cloned male and normal female by natural breeding and produced ten offspring. In this study, we investigated the puppies' temperaments, which we later compared with those of the cloned parent male. The results show that the cloned male had normal reproductive abilities and produced healthy offspring. All puppies completed narcotic detector dog training with a success rate for selection of 60%. Although the litter of cloned males was small in this study, a cloned male dog bred by natural mating produced puppies that later successfully completed the training course for drug detection. In conclusion, cloning an elite dog with superior genetic factors and breeding of the cloned dog was found to be a useful method to efficiently procure detector dogs.

Update on the First Cloned Dog and Outlook for Canine Cloning

As man's best friend, dogs have an important position in human society. Ten years ago, we reported the first cloned dog, and his birth has raised various scientific issues, such as those related to health, reproduction, and life span. He has developed without any unique health issues. In this article, we summarize and present perspectives on canine cloning.

Early embryonic development, assisted reproductive technologies, and pluripotent stem cell biology in domestic mammals

Over many decades assisted reproductive technologies, including artificial insemination, embryo transfer, in vitro production (IVP) of embryos, cloning by somatic cell nuclear transfer (SCNT), and stem cell culture, have been developed with the aim of refining breeding strategies for improved production and health in animal husbandry. More recently, biomedical applications of these technologies, in particular, SCNT and stem cell culture, have been pursued in domestic mammals in order to create models for human disease and therapy. The following review focuses on presenting important aspects of pre-implantation development in cattle, pigs, horses, and dogs. Biological aspects and impact of assisted reproductive technologies including IVP, SCNT, and culture of pluripotent stem cells are also addressed.

Production of offspring from cloned transgenic RFP female dogs and stable generational transmission of the RFP gene

The purpose of this study was to analyze the reproductive ability of transgenic female dogs born bysomatic cell nuclear transfer and to determine inheritance of the red fluorescent protein (RFP) transgene. The four founder transgenic bitches (F0) reached puberty at 340.8 ± 39.6 days after birth and were bred with wild-type male dogs by natural mating or by artificial insemination. The bitches all became pregnant and successfully delivered 13 puppies (F1), of which two females were bred with wild-type dogs to deliver 7 offspring (F2), including 1 stillbirth. Among the 19 live offspring, 10 puppies showed emission of RFP under UV light and the presence of the RFP transgene was confirmed by genomic PCR and Southern blot analyses. In conclusion, transgenic RFP female dogs exhibited normal reproductive ability and expression of the transgene was demonstrated in F1 and F2 generations.